Shape memory and superelasticity : advances in science and technology最新文献

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Rotary Bend Fatigue of Nitinol to One Billion Cycles. 镍钛诺的旋转弯曲疲劳达到十亿次循环。

Shape memory and superelasticity : advances in science and technology Pub Date : 2023-01-18 DOI: 10.1007/s40830-022-00409-7

J D Weaver, G M Sena, K I Aycock, A Roiko, W M Falk, S Sivan, B T Berg

{"title":"Rotary Bend Fatigue of Nitinol to One Billion Cycles.","authors":"J D Weaver, G M Sena, K I Aycock, A Roiko, W M Falk, S Sivan, B T Berg","doi":"10.1007/s40830-022-00409-7","DOIUrl":"10.1007/s40830-022-00409-7","url":null,"abstract":"Nitinol implants, especially those used in cardiovascular applications, are typically expected to remain durable beyond 108 cycles, yet literature on ultra-high cycle fatigue of nitinol remains relatively scarce and its mechanisms not well understood. To investigate nitinol fatigue behavior in this domain, we conducted a multifaceted evaluation of nitinol wire subjected to rotary bend fatigue that included detailed material characterization and finite element analysis as well as post hoc analyses of the resulting fatigue life data. Below approximately 105 cycles, cyclic phase transformation, as predicted by computational simulations, was associated with fatigue failure. Between 105 and 108 cycles, fractures were relatively infrequent. Beyond 108 cycles, fatigue fractures were relatively common depending on the load level and other factors including the size of non-metallic inclusions present and the number of loading cycles. Given observations of both low cycle and ultra-high cycle fatigue fractures, a two-failure model may be more appropriate than the standard Coffin-Manson equation for characterizing nitinol fatigue life beyond 108 cycles. This work provides the first documented fatigue study of medical grade nitinol to 109 cycles, and the observations and insights described will be of value as design engineers seek to improve durability for future nitinol implants.","PeriodicalId":74796,"journal":{"name":"Shape memory and superelasticity : advances in science and technology","volume":"9 ","pages":"50-73"},"PeriodicalIF":0.0,"publicationDate":"2023-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10228025/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9945192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nitinol Release of Nickel under Physiological Conditions: Effects of Surface Oxide, pH, Hydrogen Peroxide, and Sodium Hypochlorite. 生理条件下镍钛诺镍的释放:表面氧化物、pH、过氧化氢和次氯酸钠的影响。

Shape memory and superelasticity : advances in science and technology Pub Date : 2022-06-01 DOI: 10.1007/s40830-022-00364-3

Eric M Sussman, Huiyu Shi, Paul A Turner, David M Saylor, Jason D Weaver, David D Simon, Pavel Takmakov, Shiril Sivan, Hainsworth Y Shin, Matthew A Di Prima, Dianne E Godar

{"title":"Nitinol Release of Nickel under Physiological Conditions: Effects of Surface Oxide, pH, Hydrogen Peroxide, and Sodium Hypochlorite.","authors":"Eric M Sussman, Huiyu Shi, Paul A Turner, David M Saylor, Jason D Weaver, David D Simon, Pavel Takmakov, Shiril Sivan, Hainsworth Y Shin, Matthew A Di Prima, Dianne E Godar","doi":"10.1007/s40830-022-00364-3","DOIUrl":"https://doi.org/10.1007/s40830-022-00364-3","url":null,"abstract":"Nitinol is a nickel-titanium alloy widely used in medical devices for its unique pseudoelastic and shape-memory properties. However, nitinol can release potentially hazardous amounts of nickel, depending on surface manufacturing yielding different oxide thicknesses and compositions. Furthermore, nitinol medical devices can be implanted throughout the body and exposed to extremes in pH and reactive oxygen species (ROS), but few tools exist for evaluating nickel release under such physiological conditions. Even in cardiovascular applications, where nitinol medical devices are relatively common and the blood environment is well understood, there is a lack of information on how local inflammatory conditions after implantation might affect nickel ion release. For this study, nickel release from nitinol wires of different finishes was measured in pH conditions and at ROS concentrations selected to encompass and exceed literature reports of extracellular pH and ROS. Results showed increased nickel release at levels of pH and ROS reported to be physiological, with decreasing pH and increasing concentrations of hydrogen peroxide and NaOCl/HOCl having the greatest effects. The results support the importance of considering the implantation site when designing studies to predict nickel release from nitinol and underscore the value of understanding the chemical milieu at the device-tissue interface.","PeriodicalId":74796,"journal":{"name":"Shape memory and superelasticity : advances in science and technology","volume":"8 ","pages":"98-106"},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10502700/pdf/nihms-1930291.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10672526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Effect of Applied Potential on Fatigue Life of Electropolished Nitinol Wires. 施加电位对电抛光镍钛诺丝疲劳寿命的影响。

Shape memory and superelasticity : advances in science and technology Pub Date : 2017-09-01 DOI: 10.1007/s40830-017-0109-0

Shiril Sivan, Matthew Di Prima, Jason D Weaver

{"title":"Effect of Applied Potential on Fatigue Life of Electropolished Nitinol Wires.","authors":"Shiril Sivan, Matthew Di Prima, Jason D Weaver","doi":"10.1007/s40830-017-0109-0","DOIUrl":"https://doi.org/10.1007/s40830-017-0109-0","url":null,"abstract":"Nitinol is used as a metallic biomaterial in medical devices due to its shape memory and pseudoelastic properties. The clinical performance of nitinol depends on factors which include the surface finish, the local environment, and the mechanical loads to which the device is subjected. Preclinical evaluations of device durability are performed with fatigue tests while electrochemical characterization methods such as ASTM F2129 are employed to evaluate corrosion susceptibility by determining the rest potential and breakdown potential. However, it is well established that the rest potential of a metal surface can vary with the local environment. Very little is known regarding the influence of voltage on fatigue life of nitinol. In this study, we developed a fatigue testing method in which an electrochemical system was integrated with a rotary bend wire fatigue tester. Samples were fatigued at various strain levels at electropotentials anodic and cathodic to the rest potential to determine if it could influence fatigue life. Wires at potentials negative to the rest potential had a significantly higher number of cycles to fracture than wires held at potentials above the breakdown potential. For wires for which no potential was applied, they had fatigue life similar to wires at negative potentials.","PeriodicalId":74796,"journal":{"name":"Shape memory and superelasticity : advances in science and technology","volume":"3 ","pages":"238-249"},"PeriodicalIF":0.0,"publicationDate":"2017-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s40830-017-0109-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"10294528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5